The present invention relates to the manufacture of smokable materials, and in particular to the processing of tobacco products using extrusion technology.
Cured tobacco leaf conventionally undergoes several processing steps prior to the time that the resulting cut filler is provided. For example, tobacco leaves are threshed in order to separate the tobacco laminae from the stem. The tobacco laminae undergo further processing resulting in cut filler, while the stems are discarded or employed in the manufacture of reclaimed tobacco products which are traditionally of relatively low quality.
The handling, threshing and storing stages of conventional tobacco leaf processing steps result in the formation of considerable amounts of wasted tobacco material. In particular, typical processing conditions cause the formation of relatively large amounts of dust and fines. Such dust and fines are of such a small size as to be of essentially no use in the manufacture of cigarettes. However, it is possible to retrieve some of the dust and fines, and employ these materials with tobacco stems in the manufacture of reclaimed tobacco materials. Numerous references address methods for providing reclaimed or reconstituted tobaccos. See, for example, U.S. Pat. No. 3,480,018 to Fairchild.
U.S. Pat. No. 3,203,432 to Green et al proposes grinding tobacco to a small size, mixing the tobacco with water, and extruding the moist mixture into filamentary form. However, the reference proposes extruding the mixture so as to release the inherent gumminess of the tobacco. The reference does not propose the use of any binding agent additive in the disclosed process.
U.S. Pat. No. 4,598,721 to Stiller et al proposes producing crimped fiber pieces from tobacco waste using an extruder having a die head for producing filiform products and a rotating blade at the die head. Although the references proposes the use of a binder, the reference contains no teaching or suggestion of a particular binding agent.
U.S. Pat. No. 3,932,081 to Buchmann et al proposes extruding smokable fibers from a suspension of ground tobacco. The proposed suspension is an aqueous slurry of sodium carboxymethylcellulose and other additives.
U.S. Pat. No. 4,347,855 to Lanzillotti et al and U.S. Pat. No. 4,391,285 to Burnett et al propose extruding smoking articles having highly specific shapes and configurations as well as controlled porosities and densities. However, the proposed processes do not suggest the extrusion of smokable materials using binding agent additives. Rather, the references propose a release of the natural binding agents of tobacco during the extrusion process.
U.S. Pat. Nos. 4,510,950 and 4,625,737 to Keritsis et al propose providing foamed, extruded tobacco-containing smoking articles. In particular, a wet blend of tobacco dust and a cellulosic binder is extruded such that the resulting extrudate (which preferably has a cylindrical rod shape) is formed.
It would be highly desirable to provide an efficient and effective process for providing smokable materials using extrusion technology.